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AK4396 plays Fs from 44.1 kHz to 192kHz and DSD64 according to its’
datasheet; Proprietary solution for 352.8 kHz, 384 kHz and DSD128.
Configuration from PCM to DSD data format and back, is done by PIC1823
microcontroller, which 0.5sec after his work is done, is putted on sleep mode not
to insert disturbances.
By pressing the button once, one changes the state of roll-off filter. If Led F is
on –Slow roll-off filter. If Led F is off –Sharp roll-off filter.
If one wants the AK4396 to be in power-down mode (PDN), one has to press
and hold the button down until the Led F starts to blink. In this mode S/PDIF
output of I2SoverUSB board is working. Hence disturbances from AK4396 are
reduced. Getting out of PDN mode is done by holding the button down until the
Led F starts to blink.
The AK4396 remember his old filter state.
Reconstruction filter is made of MELF Vishay resistors and polyester
capacitors.
If you use both boards together there are three ways for power supply.
1. Two boards are powered from USB bus. Default state. Galvanic isolation
is avoided (on I2SoverUSB board, USB jumper is installed and on
AK4396 board, configuration jumpers are installed).
2. External power supply for the AK4396 board: 5.2V/0.2A on pin9 and
pin10. This power supply is feeding AK4396 and generators and reclocks
on I2SoverUSB board. On I2SoverUSB board, USB jumper is installed
and on AK4396 board, configuration jumpers are opened.
3. External power supply for the AK4396 board: 5.2V/0.2A on pin9 and
pin10. This power supply is feeding AK4396 and generators and reclocks
on I2SoverUSB board. External power supply for USB part 3.8V to
5.0V/0.4A on pin11 and pin12. On I2SoverUSB board, USB jumper is
opened and on AK4396 board, configuration jumpers are opened. In this
way I2SoverUSB board consumes less than 10mA from USB host.